Plagiarism is avoidable by making sure you always give credit to the original source. If you use work you previously published in your ETD you will have to provide a complete citation to the earlier publication.

Several disciplines, particularly in the health sciences, use a three paper format for dissertations. In these disciplines, students use three previously published manuscripts as the body of their ETD.

Even if you are the author of the article(s), you will still need to make sure that you have the proper copyright permissions to include the article in your ETD. You can find more information on securing permission on the ETD website.